Radrizzani confirmed in an interview with The Times that one of the investment proposals is from Qatar Sports Investments and could help Leeds "compete with Manchester City".
QSI, which controls Paris St Germain, is run by Radrizzani's friend Nasser al-Khelaifi, who has worked closely with the Italian sports and media tycoon on several football TV rights deals.
Radrizzani has not divulged the identities of the two other parties, whose investment offers he is also considering.
"I have been approached by more than 20 parties and I have selected these three," said Radrizzani, who will this week help Leeds celebrate their centenary.
"The option of Qatar Sports Investments and Nasser - first of all they are friends, we have had a good relationship for a long time.
"Secondly, they have the possibility to bring this club to compete with Manchester City, so for the fans that could be a fantastic opportunity.
"The second is based in America, he's a big fan of Leeds United since he was a child, and I like that.
"Another one is the owner of an Italian club. With another club you can create synergy to be more competitive and to target the Premier League - we could maybe get a loan to increase the quality of the team."
Radrizzani, who bought Leeds from fellow Italian Massimo Cellino in December 2016, sold a 10 per cent stake in the club to 49ers Enterprises, the financial arm of NFL franchise the San Francisco 49ers, in May 2018.
"The most important thing for me is to make this club big again," he said.
"When I will open the door to others I don't know, hopefully when we are in the Premier League. The financial support would be more important in the Premier League."
Radrizzani said he had invested over £90million in Leeds and that Marcelo Bielsa and his coaching staff costs the club £6m a year. Annual player salaries amounted to around £30m, he said.
"It's financially not sustainable to keep this level of salary, which is now over £30m, probably £33m with Marcelo and closer to £40m with the coaches," he added.
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